Emergency elevator evacuation of tall buildings

ABSTRACT

Means are provided for connecting together the hoist rope traction sheaves of two elevators in the event of power failure. The hoist ropes for one elevator pass around guide sheaves to reverse their normal direction of wrap on the traction sheave so that the two elevators travel in opposite directions when their traction sheaves are connected together. Thus, each descent of a loaded car will pull up an empty car whereby a building may be evacuated by the gravity operation of two elevators without electrical power. The two elevators are normally operable independently of each other.

0. United States Patent 1 1 3,559,768

[72] Inventor Henry P. Cox [56] References Cited 8 Banner Apts.. 1425 SW. Clay St.. UNITED STATES N S Oreg- 97201 1208,60? l2/l9l6 Mayer 187/20 QE J' $3 1969 2504.206 4/1950 Kunzelman I87/27 1 e [45] Patented Primary Examinerl-larvey C. Hornsby Feb. 2. 197] [54] EMERGENCY ELEVATOR EVACUATION OF Attorney-Lee R. Schermerhom ABSTRACT: Means are provided for connecting together the hoist rope traction sheaves of two elevators in the event of power failure. The hoist ropes for one elevator pass around guide sheaves to reverse their normal direction of wrap on the traction sheave so that the two elevators travel in opposite directions when their traction sheaves are connected together. Thus, each descent of a loaded car will pull up an empty car whereby a building may be evacuated by the gravity operation of two elevators without electrical power. The two elevators are normally operable independently of each other.

I PATENTED FEB 2 15m INVENTOR. HENRY F? COX EMERGENCY ELEVATOR EVACUATION OF TALL BUILDINGS BACKGROU ND OF THE INVENTION This invention relates to means for the gravity operation of a pair of elevators to evacuate tall buildings in the .event oflack of power to operate the'elevator motors.

In the event of electrical power failure, the elevators in a building are immediately immobilized. The only escape for occupants of the upper floors of tall buildings is a long and arduous descent by stairway. It would be highly desirable to utilize at least some of the existing elevators for evacuation when the power failure is of long duration.

Objects of the invention are, therefore, to provide means for the utilization of elevators for evacuation of a building in the eventof power failure, to provide means for operating elevators by gravity, to provide means for connecting two elevators together so that each descent of a loaded elevator will pull up an empty elevator, and to provide a system of the type described in which the evacuation elevators are available for normal operation independently of each other when power is restored.

SUMMARY OF THE INVENTION The present invention utilizes two adjacent elevators for such emergency operation. Means are provided for connecting their hoist rope traction sheaves together with the hoist ropes arranged so that the elevators travel in opposite directions. When an empty elevator is loaded at an upper floor, it descends by gravity, pulling up an empty elevator to receive the next load. The two elevators alternate in taking people down to street level. When the power has been restored, the two traction sheaves are disconnected from each other and the elevators resume normal independent operation.

The invention will be better understood and additional objects and advantages will become apparent from the following description of the preferred embodiment illustrated on the accompanying drawing. Various changes may be made in the details of construction and arrangement of parts and certain features may be employed without others. All such modifications within the scope of the appended claims are included in the invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevation view of a pair of elevator traction machines embodying the principles of the invention and showing the coupling disengaged;

FIG. 2 is a diagrammatic view on the line 2-2 in FIG. 1;

FIG. 3 is a diagrammatic view on the line 3-3 in FIG. 1;

FIG. 4 is an enlarged view of the coupling in FIG. 1, with parts in section, showing the coupling engaged; and

FIG. 5 is a view on the line 5-5 in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 2 shows a conventional elevator installation wherein the car A is suspended by hoist ropes l trained over the traction sheave 11 on the shaft 12 of a single wrap traction machine 13 at the top of the elevator shaft. As shown in FIG. 1, the traction machine 13 also includes an electric motor 14 for driving the shaft 12 and a brake drum l integral with traction sheave 11. Brake drum 15 contains a conventional service brake which is spring actuated and solenoid retracted. Electrical controls in the car start, stop and reverse the motor 14 and apply and release the brake at 15. Such controls may be of the type for use by an employee operator or of the pushbutton type for use by the passengers.

I-Ioist ropes 10 for the car A are trained around a deflector sheave l9 and connected with the upper end of a counterweight C. Compensating ropes are trained around a compensating sheave 21 in the bottom of the elevator shaft and are connected at their ends to the bottom of car A and the bottom of counterweight C The structure thus far described is conventional except that shaft 12 is extended beyond the usual length for a purpose which will presently appear.

Traction machine 23 is identical to traction machine 13 but is preferably reversed end for end as shown. Thus, traction machine 23 has an electric motor 14 for driving a shaft 24 which carries a traction sheave 25 having an integral brake drum 15 containing a service brake as described in connection with traction machine 13. Shaft 24 is aligned with shaft 12 with the adjacent ends of the two shafts spaced a short distance apart.

Referring now to FIG. 3, the car B is suspended by hoist ropes 30 trained around traction sheave 25 and guide sheaves 31, 32 and 33, the opposite end of the hoist ropes being connected to the upper end of counterweight D. Compensating ropes 35 are trained around compensating sheave 36 at the bottom of the shaft with the opposite ends of these ropes connected to the bottom of car B and the bottom of counterweight D.

The end for end reversal of traction machine 23 and the arrangement of guide sheaves 31, 32 and 33 allow the motor 14 in traction machine 23 to operate in its normal up and down directions of rotation. Thus, it will be observed that traction sheave 11 and shaft 12 on traction machine 13 rotate clockwise to raise car A, as viewed in FIG. 2 from the sheave end of the traction machine. As viewed from the opposite end of the shaft, the direction of rotation to lift the car would be counterclockwise which is the direction of rotation of the other traction unit shaft 24 and traction sheave 25 in FIG. 3 where the traction machine is turned end for end.

By reason of the described arrangement of the hoist ropes 30 in FIG. 3, the motor of traction machine 23 operates in its normal up and down directions of rotation whereby there is no alteration of the usual operating controls for either car. Car B is equipped with the same controls as described in connection with car A. As thus far described, the two elevators are adapted for normal independent operation.

The coupling shown in FIG. 4 is utilized to connect the shafts l2 and 24 together for operation of the cars A and B by gravity when there is no power to energize the motors 14. The ends of the shafts are splined at 39 to receive the splined coupling members 40 and 41. Coupling member 40 may be secured in fixed longitudinal position on shaft 24 by suitable means as exemplified by setscrew 42. Coupling member 40 has a plurality of holes 43 to receive projections 44 on coupling member 41 when the two coupling members are clamped together by bolts 45. In normal operation of the elevators the bolts 45 are removed and coupling member 41 is backed away to position 41a and secured in such position by setscrew 46 as shown in FIG. 1.

Coupling member 40 is equipped with a brake drum 50 which is engaged by abrake band 51. In the present embodiment, this brake is manually actuated by a hand lever 52 but, if desired, it may be arranged for electrical operation from an auxiliary power supply. Openings 53 provide ventilation for cooling the brake drum 50.

For effective use of the present system, the office of the building engineer is preferably located on the top floor of the building so that the engineer has ready access to the traction machines 13 and 23 of the evacuation elevators A and B. The floor indicators for these elevators are arranged for observation in the cars as usual and also at an emergency control station adjacent the traction machines. At such control station the building engineer can ascertain the locations of the elevators at the time of power failure.

Such control station is also equipped with a standby emergency power supply, such as batteries, for talking or otherwise signalling to persons in the cars A and B and for operating the service brakes in brake drums 15. The brakes and communication system require relatively little power in comparison with the amount of power used by the large hoisting motors 14. The car doors and the elevator shaft doors on all floors are arranged for manual operation from both inside and outside by means of a special tool or otherwise during power failure.

Upon the occurrence of power failure. the engineer dispatches special operators to the floors where the cars A and B are immobilized. if there are no operators already in the cars. One of the cars would then be filled with a sufficient number of passengers to exceed the weight of its counterweight, causing the car to descend to the street floor-and the other car, if already filled with passengers. would be emptied so that its counterweight would pull it to the top floor. The weight of the counterweight is usually approximately equal to the weight of the empty car plus forty percent of the weight of p the rated live load whereby a car carrying more than forty percent of its rated load will descend freely by gravity and a car carrying less than forty percent of its rated load will rise freely by gravity.

These separate gravity movements are controlled by the engineer at the emergency station operating the service brakes from the auxiliary power supply by means of emergency controls. During these movements the engineer knows the position of the moving car at all times by observation of the floor indicator at his emergency station and is in signal or voice communication with the operator in the car. Precise leveling of a car at each stop is not necessary in an evacuation emergency.

Then, with one car positioned at the street floor and the other car positioned at the top floor, the coupling members 40 and 41 are connected together by means of bolts 45. When the two elevators are thus connected together, the cars A and B with only an operator in each car balance each other and the counterweights C and D balance each other because the hoist ropes wrap the traction sheave 25 in a reverse direction relative to the wrap of the hoist ropes 10 on traction sheave 11. The two cars can move only in opposite directions. Some form of positive connecting means which cannot be accidentally disconnected, as exemplified by bolts 45, is preferred for safety.

The car at the top floor is then filled with passengers and allowed to descend to the street floor, pulling the empty car from the street floor to the top floor. This operation is repeated, using the two elevators alternately, until the top floor has been evacuated.

A different procedure is necessary for evacuating the floors below the top floor. Assume, for example, that car A is descending with its operator and last load of passengers from the top floor of a fifty story building and pulling up car B which is empty except for its operator. The engineer stops the cars when car B reaches the 49 th floor and a half load is admitted into car B. Then the engineer releases the brakes, allowing car A with its full load to continue to the street floor, pulling the half load in car B up to the top floor. When car A has discharged its load, the half load in car B causes car B to descend, pulling up car A which is now empty except for its operator. The engineer then stops descending car B at the 49th floor to make up its full load.

Car B is then allowed to descend until the empty car A reaches the 49 th floor whereupon the engineer again stops the cars and this time the operator in car A admits a half load. Then the full load in car B descends, pulling car A with its half load to the top floor and car B discharges on the street floor.

A similar procedure is followed in evacuating the 48 th and lower floors. Assume that car A is now descending from the 49the floor with its last full load and pulling up empty car B. When empty car B reaches the 48 th floor, the engineer stops the cars and the operator in car B admits a half load from the 48 th floor. Then car A continues to the street floor with its full load, pulling up car B with its half load to the top floor. After car A has discharged its load on the street floor, car B is allowed to descend and stop again at the 48 th floor to complete a full load and descend until empty car A rises to the 48 th floor. This procedure is repeated from floor to floor until all the upper floors have been evacuated. If a few people are left on any floor after the last full car load departs, those people can walk down the stairs to the next floor below.

The movements just described could also be controlled by the hand brake 51 which is available if needed. Ordinarily, the elevator service brakes 15 would be operated from an auxiliary power supply as described and the hand brake 51 would not be used unless the auxiliary power supply lacked the capacity to complete the evacuation of the building. in such event the service rakes at 15 are held retracted temporarily by mechanical means.

It is also possible to control the gravity evacuation movements of the two cars directly by the operators in the cars by means of special emergency control circuits for actuating the service brakes 15 from the auxiliary power supply. The two operators in cars A and B are in communication with each other as well as with the engineer at the traction machines 13 and 23 in order to coordinate the movements of the cars with the loading and unloading of the cars and the opening and closing of the doors.

It is also within the spirit of the invention to operate the relatively small elevator door motors from such an auxiliary power supply controlled by the operators within the cars in order to obviate the necessity for manual operation of the doors. This depends on the capacity of the auxiliary power supply.

Although the cars have been described as going up empty, except for the operator, a few passengers could also ride up in each trip, if desired.

It is not essential that shafts 12 and 24 be in axial alignment in order to be coupled together. These shafts may be disposed in some different relationship and suitable coupling or connecting means provided to effect operation of the elevators in the manner described.

When power is restored after an emergency, the bolts 45 are removed and coupling member 41 is disengaged from coupling member 40. Then the elevators may resume normal independent operation by their motors l4.

lclaim:

1. An emergency elevator system for the evacuation of buildings in the event of power failure which prevents energization of the elevator motors, said system comprising a pair of traction machines each having a motor driven traction sheave with electrically controlled brake means for normal independent operation, a pair of elevator cars each suspended by hoist ropes passing over one of said traction sheaves and connected to a counterweight, and disengageable means for connecting said traction sheaves of the two traction machines together, said hoist ropes being so arranged on said traction sheaves that the two cars and counterweights balance each other with one car moving up when the other car moves down whereby a car carrying a greater load will descend by gravity and pull up the other car carrying a lesser load when said motors are deenergized and said traction sheaves are connected together, said two cars being normally operable independently of each other by said motors when said traction sheaves are not connected together and a power supply is available for said motors.

2. A system as defined in claim 1, said two traction sheaves having shafts arranged in axial alignment with each other, said means for connecting the two sheaves together comprising interengageable coupling members on adjacent ends of said shafts.

3. A system as defined in claim 2 including guide sheaves arranged to reverse the direction of wrap of the hoist ropes of one car on its traction sheave relative to the direction of wrap of the hoist ropes of the other car on its traction sheave.

4. A system as defined in claim 3, one of said traction machines being reversed end for end relative to the other traction machine whereby the normal up and down directions of rotation are maintained for both machines.

5. A system as defined in claim 2 including a mechanical brake on one of said coupling members. 

1. An emergency elevator system for the evacuation of buildings in the event of power failure which prevents energization of the elevator motors, said system comprising a pair of traction machines each having a motor driven traction sheave with electrically controlled brake means for normal independent operation, a pair of elevator cars each suspended by hoist ropes passing over one of said traction sheaves and connected to a counterweight, and disengageable means for connecting said traction sheaves of the two traction machines together, said hoist ropes being so arranged on said traction sheaves that the two cars and counterweights balance each other with one car moving up when the other car moves down whereby a car carrying a greater load will descend by gravity and pull up the other car carrying a lesser load when said motors are deenergized and said traction sheaves are connected together, said two cars being normally operable independently of each other by said motors when said traction sheaves are not connected together and a power supply is available for said motors.
 2. A system as defined in claim 1, said two traction sheaves having shafts arranged in axial alignment with each other, said means for connecting the two sheaves together comprising interengageable coupling members on adjacent ends of said shafts.
 3. A system as defined in claim 2 including guide sheaves arranged to reverse the direction of wrap of the hoist ropes of one car on its traction sheave relative to the direction of wrap of the hoist ropes of the other car on its traction sheave.
 4. A system as defined in claim 3, one of said traction machines being reversed end for end relative to the other traction machine whereby the normal up and down directions of rotation are maintained for both machines.
 5. A system as defined in claim 2 including a mechanical brake on one of said coupling members. 